Hi Henry,
Thank you for clarifying your findings: "from what I have implemented and heard is that an unregulated analog power supply seem to always sound better than those with SMPS. And this is strictly in the context of class D Icepower." I understand you're in the midst of experimenting to determine if the same holds true for Hypex NCore 400 modules.
I'm not really surprised that Hypex didn't allow you access to their top NCore 1200 module. I've read that Hypex had a predetermined sales strategy to reserve the NCore 1200 module for the larger OEM market while offering the NCore 400 module for sale to the DIY market and amp assembly market. I believe Hypex is considering H2O a segment of the amp assembly market even though we, and likely many others, realize H2O actually more closely resembles an OEM than an amp assembler.
I assume you're aware of the newest Hypex module, the NCore 500, which supposedly is very similar to the sound quality of the NCore 1200 but not quite as powerful. There is even a U.K. company somewhat similar to H2O, Nord, that offers stereo and mono-block amps based on the NCore 500 module that use Hypex smps but have discrete class A input buffer boards that allow a choice of op amps (Sparkos SS3602 or Sonic Imagery 994). Maybe this will be the future of class D, with op amp rolling rather than tube rolling.
There are also many very good alternative class D power modules such as the Anaview/Abletech ALC-1000-1300 (used in the D-Sonic M3-600-M mono-blocks) that utilize Phase Shifting Modulation (PSM) rather than the Pulse Width Modulation (PWM) that Hypex NCore modules utilize and the Pascal modules (used in the D-Sonic M3-1500-M and M3-800-S, Red Dragon S500, Jeff Rowland Continuum S2 integrated and 525 stereo amps) that feature their proprietary and patented UMAC technology. I believe these modules would be available to you and could possibly be enhanced with your custom analog power supplies.
Thanks,
Tim